Coming back on an external link

Hi all,
I install in-app-browser and I open a new window from my app to load an external link but it doesn’t come back into my app… why?
I just do it

<a class="button button-icon icon ion-social-facebook" onclick="window.open('https://www.facebook.com/pages/MCE-ITALIA/1426859354199693','_system','location=no'); return false;"></a>

Thanks

so the in app browser opens and if you click on “done”, what happens?

i use the plugin also, but with different params

window.open(URL, '_blank', 'location=yes');
// no return false

see https://github.com/apache/cordova-plugin-inappbrowser

its doesnt work…
because if I press button back on my phone it doesnt return the back page